Busy in Baltimore: Mayor Bloomberg waiting to speak at a gun-violence summit while his aides were bungling teacher-evaluation talks back home. Photo: AP

Remember the time Mike Bloomberg jetted off to sunny Bermuda as a monster snowstorm bore down on the five boroughs? Never again, he said afterward, woefully, while the city ever-so-slowly dug itself out of the drifts.

Well, some tigers just can’t change their stripes.

For there he was last week, down in Maryland giving America a firearms intervention while the United Federation of Teachers and his own crack Department of Education negotiators pulled his pants down on teacher-quality reform.

Transforming the city’s public-school system into a national model for quality and effectiveness was once right at the top of Mayor Mike’s personal legacy list.

But then came the third-term blahs, the departure of Joel Klein as schools chancellor, the ensuing Cathy Black debacle, the ascendancy of the thuggish United Federation of Teachers boss Mike Mulgrew — and the now-pervasive sense that Bloomberg no longer much gives a damn about the city’s 1,400 schools.

Fact is, he’s always been long on big ideas and short on follow-through (congestion pricing, anyone?). The schools seem to be no different.

Bloomberg won mayoral control of the Board of Education early on — a signal victory, though one built on the largely unappreciated efforts of his predecessor, Mayor Rudy Giuliani. Then came a lot of churning, but not much change.

Certainly not when it came to dealing with Albany.

He dispatched naïve deputies to the capital city to negotiate charter-school and school-closure reform with Assembly Speaker Sheldon Silver — and wound up with laws studded with subsections designed to weaken, not strengthen, mayoral control.

And that’s how it worked out.

Fast forward to last week’s teacher-evaluation horror show, a repeat of what had come before: Mike delegated, his deputies dithered and the UFT carried the day

More, the union can now credibly — if dishonestly — argue that the potential loss of hundreds of millions in state and federal school aid is all Mike’s fault.

The money is the carrot in a state law requiring that the city and its unions negotiate objective evaluation standards for teachers and supervisors.

This always was going to be a tough fight. Mulgrew would sooner jam hot needles in his eyes than allow even the most egregiously incompetent teachers to be dismissed.

But as negotiations closed in on last Thursday’s deadline, the union had an unexpected ally at the table: Shael Polakow-Suransky, the policy factotum forced on Bloomberg by Albany as its price for allowing Cathy Black to become chancellor.

Black imploded after just weeks on the job, but Polakow-Suransky remained.

And Polakow-Suransky, it seems, is no fan of standardized testing, a key tool — if not the key tool — in any credible teacher-evaluation regimen.

“He doesn’t believe in testing,” says one high-ranking participant in the talks. “He negotiated it away — and when Mike [came back and] found out, he exploded.”

This brought negotiations to an end in a spray of invective, with state Education Commissioner John King essentially (and not unreasonably) blaming the breakdown on Bloomberg while threatening to withhold perhaps $1 billion in education aid from the city.

Still, you can’t perform an education on a child, like an appendectomy. It’s a process, and many children — for reasons of class, culture, economic circumstance or personal disinclination to participate — resist it more than others.

These are the children who desperately need the readin’, ’ritin’ and ’rithmatic rubric that comprises the core of most test prep.

And in that sense, test performance is an entirely valid — indeed, critical — standard against which to judge teachers.

So if Polakow-Suransky doesn’t like standardized testing — well, too bad about Polakow-Suransky. And no matter that such views enjoy considerable currency among the Columbia Teachers College crew that drives policy at the Department of Education; they have no legitimate presence in Bloomberg administration negotiating positions.

And they certainly shouldn’t have come as such a surprise to the mayor himself.

That is, Mike should have been paying much closer attention to what was being proposed in his name.

For while education isn’t as sexy as assault rifles, he started the reform fight. He really should devote what time he has remaining in City Hall to working for its successful conclusion.